| 61. |
- Abazov, V. M., et al.
(författare)
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Search for Higgs boson production in trilepton and like-charge electron-muon final states with the D0 detector
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052009-
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Tidskriftsartikel (refereegranskat)abstract
- We present a search for Higgs bosons in multilepton final states in p (p) over bar collisions at root s = 1.96 TeV recorded with the D0 detector at the Fermilab Tevatron Collider, using the full Run II data set with integrated luminosities of up to 9.7 fb(-1). The multilepton states considered are ee mu, e mu mu, mu tau(h)tau(h) , and like-charge e(+/-) mu(+/-) pairs. These channels directly probe the HVV (V = W, Z) coupling of the Higgs boson in production and decay. The mu tau(h)tau(h) channel is also sensitive to H -> tau(+)tau(-) decays. Upper limits at the 95% C.L on the rate of standard model Higgs boson production are derived in the mass range 100 <= M-H <= 200 GeV. The expected and observed limits are a factor of 6.3 and 8.4 above the predicted standard model cross section at M-H = 125 GeV. We also interpret the data in a fermiophobic Higgs boson model.
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| 62. |
- Abazov, V. M., et al.
(författare)
-
Search for the Higgs boson in lepton, tau, and jets final states
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052005-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9:7 fb(-1) of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H -> tau tau decays or H -> WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0, respectively.
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| 63. |
- Abazov, V. M., et al.
(författare)
-
Search for the rare decay B-s(0) -> mu(+) mu(-)
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 87:7, s. 072006-
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Tidskriftsartikel (refereegranskat)abstract
- We perform a search for the rare decay B-s(0) -> mu(+) mu(-) using data collected by the D0 experiment at the Fermilab Tevatron Collider. This result is based on the full D0 Run II data set corresponding to 10.4 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV. We use a multivariate analysis to increase the sensitivity of the search. In the absence of an observed number of events above the expected background, we set an upper limit on the decay branching fraction of B(B-s(0) -> mu(+) mu(-)) < 15 x 10(-9) (12 x 10(-9)) at the 95% (90%) C.L.
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| 64. |
- Abazov, V. M., et al.
(författare)
-
Search for the standard model Higgs boson in lv plus jets final states in 9.7 fb(-1) of p(p)over-bar collisions with the D0 detector
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052008-
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Tidskriftsartikel (refereegranskat)abstract
- We present, in detail, a search for the standard model Higgs boson, H, in final states with a charged lepton (electron or muon), missing energy, and two or more jets in data corresponding to 9.7 fb(-1) of integrated luminosity collected at a center-of-mass energy of root s = 1.96 TeV with the D0 detector at the Fermilab Tevatron p (p) over bar Collider. The search uses b-jet identification to categorize events for improved signal versus background separation and is sensitive to associated production of the H with a W boson, WH -> lvb(b)over bar>; gluon fusion with the Higgs decaying to W-boson pairs, H -> WW -> lvjj; and associated production with a vector boson where the Higgs decays to W-boson pairs, VH -> VWW -> lvjjjj production (where V = W or Z). We observe good agreement between data and expected background. We test our method by measuring WZ and ZZ production with Z -> b(b)over bar> and find production rates consistent with the standard model prediction. For a Higgs boson mass of 125 GeV, we set a 95% C. L. upper limit on the production of a standard model Higgs boson of 5.8 sigma(SM) SM, where sigma(SM) is the standard model Higgs boson production cross section, while the expected limit is 4.7 X sigma(SM). We also interpret the data considering models with fourth generation fermions, or a fermiophobic Higgs boson.
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| 65. |
- Abazov, V. M., et al.
(författare)
-
Search for ZH -> l(+)l(-)b(b)over-bar production in 9.7 fb(-1) of p(p)over-bar collisions with the D0 detector
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:5, s. 052010-
-
Tidskriftsartikel (refereegranskat)abstract
- We present a search for the standard model Higgs boson produced in association with a Z boson in 9.7 fb(-1) of p (p) over bar collisions collected with the D0 detector at the Fermilab Tevatron Collider at root s = 1.96 TeV. Selected events contain one reconstructed Z -> e(+)e(-) or Z -> mu(+)mu(-) candidate and at least two jets, including at least one jet likely to contain a b quark. To validate the search procedure, we also measure the cross section for ZZ production and find that it is consistent with the standard model expectation. We set upper limits at the 95% C.L. on the product of the ZH production cross section and branching ratio B(H -> b (b) over bar) for Higgs boson masses 90 <= M-H <= 150 GeV. The observed (expected) limit for M-H = 125 GeV is a factor of 7.1 (5.1) larger than the standard model prediction.
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| 66. |
- Abazov, V. M., et al.
(författare)
-
Studies of W boson plus jets production in p(p)over-bar collisions at root s=1.96 TeV
- 2013
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 88:9, s. 092001-
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Tidskriftsartikel (refereegranskat)abstract
- We present a comprehensive analysis of inclusive W(-> ev) + n-jet (n >= 1, 2, 3, 4) production in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV at the Tevatron collider using a 3.7 fb(-1) data set collected by the D0 detector. Differential cross sections are presented as a function of the jet rapidities (y), lepton transverse momentum (P-T) and pseudorapidity (eta), the scalar sum of the transverse energies of the W boson and all jets (H-T), leading dijet P-T and invariant mass, dijet rapidity separations for a variety of jet pairings for P-T-ordered and angular-ordered jets, dijet opening angle, dijet azimuthal angular separations for P-T-ordered and angular-ordered jets, and W boson transverse momentum. The mean number of jets in an event containing a W boson is measured as a function of H-T, and as a function of the rapidity separations between the two highest-P-T jets and between the most widely separated jets in rapidity. Finally, the probability for third-jet emission in events containing a W boson and at least two jets is studied by measuring the fraction of events in the inclusive W + 2-jet sample that contain a third jet over a P-T threshold. The analysis employs a regularized singular value decomposition technique to accurately correct for detector effects and for the presence of backgrounds. The corrected data are compared to particle level next-to-leading-order perturbative QCD predictions, predictions from all-order resummation approaches, and a variety of leading-order and matrix element plus parton shower event generators. Regions of the phase space where there is agreement or disagreement with the data are discussed for the different models tested.
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| 67. |
- Abazov, V. M., et al.
(författare)
-
B-s(0) lifetime measurement in the CP-odd decay channel B-s(0) -> J/Psi f(0)(980)
- 2016
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Ingår i: PHYSICAL REVIEW D. - 2470-0010. ; 94:1
-
Tidskriftsartikel (refereegranskat)abstract
- The lifetime of the B-s(0) meson is measured in the decay channel B-s(0) -> J/Psi pi(+)pi(-) with 880 <= M pi+pi- <= 1080 MeV/c(2), which is mainly a CP-odd state and dominated by the f(0)(980) resonance. In 10.4 fb(-1) of data collected with the D0 detector in Run II of the Tevatron, the lifetime of the B-s(0) meson is measured to be tau(B-s(0)) = 1.70 +/- 0.14(stat) +/- 0.05(syst) ps. Neglecting CP violation in B-s(0)/(B) over bar (0)(s) mixing, the measurement can be translated into the width of the heavy mass eigenstate of the B-s(0), Gamma(H) = 0.59 +/- 0.05(stat) +/- 0.02(syst) ps(-1).
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| 68. |
- Abazov, V. M., et al.
(författare)
-
Combination of D0 measurements of the top quark mass
- 2017
-
Ingår i: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 95:11
-
Tidskriftsartikel (refereegranskat)abstract
- We present a combination of measurements of the top quark mass by the D0 experiment in the lepton + jets and dilepton channels. We use all the data collected in Run I (1992-1996) at root s = 1.8 TeV and Run II (2001-2011) at root s = 1.96 TeV of the Tevatron p (p) over bar collider, corresponding to integrated luminosities of 0.1 fb(-1) and 9.7 fb(-1), respectively. The combined result is: m(t) = 174.95 +/- 0.40(stat)+/- 0.64(syst) GeV = 174.95 +/- 0.75 GeV.
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| 69. |
- Abazov, V. M., et al.
(författare)
-
Constraints on Models for the Higgs Boson with Exotic Spin and Parity in VH -> Vb(b)over-bar Final States
- 2014
-
Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 113:16, s. 161802-
-
Tidskriftsartikel (refereegranskat)abstract
- We present constraints on models containing non-standard-model values for the spin J and parity P of the Higgs boson H in up to 9.7 fb(-1) of p (p) over bar collisions at root s = 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. These are the first studies of Higgs boson J(P) with fermions in the final state. In the ZH -> llb (b) over bar, WH -> l nu b (b) over barb, and ZH -> nu nu b (b) over bar final states, we compare the standard model (SM) Higgs boson prediction, J(P) = 0(+), with two alternative hypotheses, J(P) = 0(-) and J(P) = 2(+). We use a likelihood ratio to quantify the degree to which our data are incompatible with non-SM J(P) predictions for a range of possible production rates. Assuming that the production rate in the signal models considered is equal to the SM prediction, we reject the J(P) = 0(-) and J(P) = 2(+) hypotheses at the 97.6% CL and at the 99.0% CL, respectively. The expected exclusion sensitivity for a J(P) = 0(-)(J(P) = 2(+)) state is at the 99.86% (99.94%) CL. Under the hypothesis that our data are the result of a combination of the SM-like Higgs boson and either a J(P) = 0(-) or a J(P) = 2(+) signal, we exclude a J(P) = 0(-) fraction above 0.80 and a JP = 2(+) fraction above 0.67 at the 95% CL. The expected exclusion covers J(P) = 0(-)(J(P) = 2(+)) fractions above 0.54 (0.47).
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| 70. |
- Abazov, V. M., et al.
(författare)
-
Double parton interactions in gamma+3 jet and gamma plus b/c jet+2 jet events in p(p)over-bar collisions at root s=1.96 TeV
- 2014
-
Ingår i: Physical Review D. - 1550-7998 .- 1550-2368. ; 89:7, s. 072006-
-
Tidskriftsartikel (refereegranskat)abstract
- We determine the fraction of events with double parton (DP) Scattering in a single p (p) over bar collisions at root s = 1.96 TeV in gamma + 3 jet and gamma + b/c jet + 2 jet events collected with the D0 detector and corresponding to an integrated luminosity of about 8.7 fb(-1). The DP fractions and effective cross sections (sigma(eff)) are measured for both event samples using the same kinematic selections. The measured DP fractions range from 0.21 to 0.17, with effective cross sections in the gamma + 3 jet and gamma + b/cjet + 2 jet samples of sigma(incl)(eff) = 12.7 +/- 0.2(stat) +/- 1.3(syst) mb and sigma(HF)(eff) = 14.6 +/- 0.6(stat) +/- 3.2(syst) mb, respectively.
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